Semester Lab Research in Marine GeologyPatricia Manley, Middlebury College
The class (GEOL 0342) targets Junior and Seniors. The lab section of the course is a semester project that is original research focused on the geologic history of Lake Champlain. Students have had introductory geology courses before taking this class.
AudienceThis is an advanced geology course intended for undergraduate Geology majors, though there have been students from other disciplines (Geology, Biology and Environmental Studies) in the course.
Class size10-15 students
How the activity is situated in the courseThis is a semester project that begins the first week of classes within the lab section and culminates during the exam week with a formal presentation. For this particular class we have a well-equipped research vessel (R/V Baldwin) on a large body of water (Lake Champlain, VT-NY).
The main goals for the activity are to:
- have students conduct original research within a team setting.
- have students be able to synthesize several differing data sets (e.g. seismic profiling, side-scan sonar, piston cores, hydrographic data, sediment analysis) in achieving the understanding needed to answer the research question.
- have students do primarily literature research on a particular topic.
- introduce students to the various marine and oceanographic equipment and utilize them in a research setting.
- be able to analyze their data, write up and present their research.
- provide students the opportunity to work in a group as if they were part of a scientific team.
- Mapping the sediment layers in Lake Champlain outside Button Bay. Identify the nature of the unconformities observed.
- What is the nature of the Port Henry Delta? Does it really exist?
- What is the cause and nature of the sediment located in Whallon Bay? Can we distinguish or determine if fresh water pulses invaded this area?
- Buried river channels and subsurface marine terraces. Is there a the Port Henry water plane?
The following is an excerpt from the class assignment given a few years ago to show how the project is set up and delivered to the class.
Phase I: Identify the problem
What is the cause and nature of the sediments located in Whallon Bay? Can we distinguish or determine if fresh water pulses invaded this area?
Background: A few senior theses (Middlebury senior theses) as well as one Marine Geology class (Fall 2001, 2003, 2005) and Oceanography classes have worked in the region south of Split Rock – Thompsons Point. Lynde (1975) ran seismic lines and took cores in this region. He identified the marine sediments of the Champlain Sea as well as sediment from Lake Vermont. His seismic lines were sparse and a few cores were taken. Recent work as a result from the Fall 2003 Marine Geology class prompted further work with the United States Geological Survey (USGS) and the determination of possible fresh water pulses occurring during the last deglaciation during the period of the Champlain Sea. Whallon Bay has never been investigated using seismic profiling or cores.
Project Goals: For the overall project, you need to review the literature written concerning Lake Champlain (salient articles are in labeled folder at the back of the teaching space). Specifically you need to determine the nature of the sediments (Lake Champlain, Champlain Sea, Lake Vermont sediments) in this area. Look at the geometry of the most recent sedimentation. After reading the Cronin et al. paper (2008), what might we look at to investigate whether fresh water pulses made it into Whallon Bay?
Remember you have about six weeks on the R/V Baldwin to gather all information or samples. Tools available on the R/V Baldwin are Conductivity-Temperature-Depth profiler (CTD), Chirp seismic profiler, 14kHz reflection profiler, bottom grab sampler, piston corer, side-scan sonar and a ROV (remotely operated vehicle). Laboratory equipment for sediment analyses includes electric resistivity probe, magnetic susceptibility loop, penetrometer, Horiba grain size analyzer, Munsel color charts, Scanning electron microscope (SEM), X-ray diffractometer (XRD), techniques to determine physical properties from discrete samples, and Surfer or Earth Vision software for graphical representations. Other techniques of interest? As a group, we need to begin to formalize a scientific research plan, see how it can be implemented and what shipboard/laboratory procedures will assist us in achieving the goals.
Phase II: Define and implement the research plan
As a team, the class designs how they wish to approach answering the posed research question. For this particular class they did a series of seismic reflection profiling lines using the Chirp, 14 kHz and side-scan sonars and piston cores.They did 24 seismic profile lines and took three cores. After initiating the seismic survey the class located an underwater slump. In consultation with the faculty mentor, the research question was modified and the remainder of the project focused on delineating and understanding this underwater slump event. In conjunction with the gathering of the seismic lines, the class determined where sediment cores should be taken for optimal understanding of the sedimentary history in Whallon Bay. All figures shown here were generated by the class for inclusion in their final report
Phase III: Analyses and presentation of results
All seismic lines were digitized and the key reflectors separating the major sediment units were defined. The class analyzed the cores for physical properties using magnetic susceptibility, electric resistivity, spectrophotometry, bulk density, porosity, and grain size. All sediment analyses were conducted using standard Ocean Drilling Program practices and protocols. A final class presentation of the salient results was presented by PowerPoint and a final group research paper was submitted. Each student must present part of the oral presentation for grading purposes.
Notes, Tips, and Logistical ConsiderationsAs with doing any research, the question that was initially asked often needs to be amended. In the past ten years of doing this lab research project this has occurred nearly every time. With equipment failures or newly discovered sub-bottom features it is easy to refocus the class project. Since the professor is part of the research team (usually in a guidance and consultant role), the project can be redirected as needed. It is important to reinforce that change in scientific directions is a common practice and can often lead to new and exciting discoveries.
Research Team -- Internal Peer Review
Directions: This is a homework assignment. You will either get a 100 or Zero for turning this in on time or not. Due date: This Friday - 5 pm
Once completed: Send the spreadsheet back to me via email only
Obvious Notes of Caution: This is not to be considered lightly, consider well the grades you provide. This is not a popularity contest, rather a work-ethic evaluation. Be honest and do your best to devoid yourself of emotional bias.
Criteria for evaluation: 1) You are to evaluate the people in your research team. 2) A person's efforts in helping his/her team out over the entire term is the only measure of your evaluation. 3) You are to provide 3 numeric grades for each person. The 3 grades are for that person's SUPPORT of the team during A) Field work B) Laboratory analyses and, C) an OVERALL grade. 4) You must evaluate yourself.
Grading: All grades provided by you are to be numeric only (0-100; NO letter grades)
Use of these grades: 1) For each person, the highest and lowest grade will be removed and the remaining will be averaged to provide 10% of that person's final grade for the project 2) Your name or any grades that you provide will not be divulged.
Classmates---- Field Grade---- Laboratory Grade---- Overall Grade
Classmate name #1
Classmate name #2